Added usage description

Author: KevNetG

README.md

@@ -1 +1,21 @@
-# speech-to-text-voxforge
+# speech-to-text-voxforge
+
+## Download the speech corpus
+In order to download the speech corpus run
+
+```shell
+python downloader.py "voxforge-corpus"
+```
+
+You can additionally specify the amount of speaker directories to be downloaded using `-n` or the amount of threads to be used for the download using `-w`:
+
+```shell
+python downloader.py "voxforge-corpus" -n 20000 -w 15
+```
+
+## Generate training data
+If you want to generate a training data file for the [speech recognition tool](https://github.com/KevNetG/speech-to-text), run `generator.py` providing the path to the directory where the voxforge corpus was being downloaded and a path to the new file where the training data should be stored. The data will be stored as JSON.
+
+```shell
+python generator.py "voxforge-corpus" "training_data.json"
+```